Flexible manufacture of polyethylene terephthalate ("PET")

Abstract

In at least one embodiment, the present invention relates to a method and system for providing blends of virgin polyethylene terephthalate (VPET) and a VPET property modifying component (PCM). In one embodiment, separate sources of solid VPET and solid PMC are provided. A conduit is provided between the sources and a bulk-container, which is suitable for delivery to an end user. VPET from the source of VPET and PMC from the PMC source are selectively dispensed into the conduit in a desired amount to form a uniform blend of materials comprising a predetermined ratio of VPET relative to PMC. The blend of materials is transported to the bulk-container for delivery to an end user.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] In at least one aspect, the present invention pertains to the commercial manufacture of polyethylene terephthalate (“PET”) polymers. [0003] 2. Background Art [0004] Polyethylene terephthalate (“PET”) is an established bottle polymer that produces rigid bottles with excellent clarity and gloss. These containers are manufactured by a process that typically comprises drying the PET resin, injection molding a preform and, finally, stretch blow molding the finished bottle. [0005] In an effort to conserve resources, blends of virgin polyethylene terephthalate (“VPET”) polymer and post-consumer recycled PET (PCR) material have been used for forming PET bottles. The blends can comprise any suitable ratio, but typically comprise between 75% to 95% VPET and 5% to 25% PCR material, on a weight basis. [0006] The VPET and the recycled PET (PCR) are often provided to the bottle manufacturer by a PET supplier. To reduce inventory ...

AI Technical Summary

Benefits of technology

[0013] In at least one embodiment, each of the sources of material (VPET and PMC) is in fluid communication with a loading bin to allow delivery of the dry solid materials to the loading bin, prior to being transported to the bulk-container. In at least one embodiment, the fluid communication is preferably provided by pneumatic dense or diluted phase conveying conduits or transfer lines. In at least one embodiment, a CPU containing a blending program is provided to aid the blending process, hence reducing the possibility of human error or missed operation.

Problems solved by technology

This process can obviously be time consuming and costly as it requires additional manufacturing steps, such as crystallizing and solid stating.

This is because such premixed containers typically have other more problematic issues.

For instance, since different ratios of VPET and PCR material are required for different applications and for different end users, it is not practical to maintain various premixed containers of VPET and PCR material.

Such a practice would tend to result in an inefficient use of space, working capital and fixed capital, thus resulting in an increase in cost.

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